The present invention relates to a beverage dispenser, and, more particularly, to a beverage dispenser for partially frozen beverages with an improved drive and sealing system.
In the food service industry, various machines have been developed to produce, store, and dispense a partially frozen beverage, such as a slush-type beverage. In general, such machines mix water and a flavored component, freeze the mixture, and then dispense a partially frozen beverage product with a slush-like consistency. Such machines are often referred to as “granita” machines.
In general, such a granita machine includes a bowl for storing the beverage product. A freezing cylinder extends through the bowl and houses evaporator coils (of a refrigeration circuit) or other refrigeration means that cools the beverage product to the desired temperature. Also located within the bowl is an auger which rotates about the freezing cylinder to shave frozen beverage product off of the surface of the freezing cylinder and to circulate the beverage product within the bowl, resulting in the partially frozen or slush-like consistency of the beverage product.
In most prior art constructions, a granita machine includes a drive shaft that extends through the center of the freezing cylinder and is connected to the auger. At the rear of the granita machine, this drive shaft is operably connected to a gear arrangement and motor. For example, as shown in FIG. 1, the drive shaft 10 extends through the freezing cylinder 12, and, at the front end of freezing cylinder 12, the drive shaft 10 is connected to and drives the auger 14. Thus, such a construction requires a shaft seal 16 at the front end of the freezing cylinder 14. This shaft seal 16 is almost continuously submerged in the partially frozen beverage product and can be prone to leakage, allowing the beverage product to seep into the interior of the freezing cylinder 12. Once the partially frozen beverage product, which typically includes high amounts or sugar and is very sticky, gets into the interior of the freezing cylinder 12, it can be virtually impossible to clean it out of the freezing cylinder 12.
Commonly owned U.S. patent application Ser. No. 13/223,639 (U.S. Patent Publication No. 2012/0055189) thus describes and claims a beverage dispenser for partially frozen beverages with an improved drive and sealing system. The beverage dispenser includes one or more bowls. In each bowl, there is a freezing cylinder, and there is a dispenser assembly at the front end of each bowl for dispensing the beverage product. In each bowl, there is also an auger which rotates about each freezing cylinder to shave frozen beverage product off of the surface of the freezing cylinder and to circulate the beverage product within the respective bowls, resulting in the partially frozen or slush-like consistency of the beverage product.
The auger in such a beverage dispenser is preferably a unitary member molded from a thermoplastic material. The auger preferably includes a helical flange (or flight) that is reinforced by first and second longitudinal ribs that extend the length of the auger. At one end, the helical flange terminates in a cylindrical member that defines an internal cavity. The freezing cylinder includes a boss extending from its front surface that is received in the internal cavity defined by the cylindrical member. Thus, once assembled, the position of the auger relative to the freezing cylinder is maintained, in part, by the connection of the cylindrical member of the auger to the boss extending from the front surface of the freezing cylinder; however, the auger is still free to rotate relative to the freezing cylinder.
In each bowl, the auger is driven from the rear, and thus, there is no drive shaft that extends through the freezing cylinder. Thus, there is no shaft seal in the lower front portion of the dispenser, where it would be continuously submerged in the partially frozen beverage product.
While the beverage dispenser described and claimed in U.S. patent application Ser. No. 13/223,639 (U.S. Patent Publication No. 2012/0055189) does address some of the deficiencies of the prior art, in some applications, alternative drive systems for rotating the auger may be desirable.